1. Field of the Invention
The present invention relates to a forward compatibility guaranteed data compression and decompression method and apparatus thereof, and more particularly to a compression and decompression method and apparatus for compressing an original file to generate a compressed file and decompressing the compressed file, wherein basic data compression and decompression can be normally performed even when a file compressed in an application supporting a compressed file format of an upper version is decompressed in an application supporting a compressed file format of a lower version.
2. Description of the Related Art
Data compression technology reduces transmission time or saves a storage space by removing an unnecessary portion when data is transmitted or stored. For example, in case of sending documents by facsimile, it takes more time when sending a blank between characters or lines. Accordingly, data is compressed to reduce the transmission time by transmitting a position or size of the blank as a simplified signal or simplifying repeated data. The storage space of a storage medium can be saved by using the technology when storing data in a magnetic tape or disk.
The data compression and decompression technology mainly includes a compression algorithm and a compressed file format. That is, it is important which algorithm is used to reduce the space occupied by the data and which storage configuration is used for the information on the compressed data.
The compressed file format may have various versions with development of technology and improvement of performance. In general, a file compressed in an application supporting a compressed file format of a lower version can be decompressed without any problems in an application supporting a compressed file format of an upper version. This is because a configuration of a compressed file is designed considering backward compatibility based on a lower version when upgrading a version of the compressed file.
However, in an opposite case, i.e., when a file compressed in an application supporting a compressed file format of an upper version is decompressed in an application supporting a compressed file format of a lower version, a problem may occur. This is because a compressed file including a compressed file format configuration or the like which is newly added in an upper version may not be recognized in a lower version. Therefore, there is a demand for a forward compatibility guaranteed compressed file format capable of performing basic data decompression on a compressed file stored in a compressed file format of an upper version.